This invention relates to electrical apparatus for electrocauterization of living tissue in a surgical procedure, and more specifically, to such apparatus particularly useful for sealing the lumen of a vas or other tubular vessel, for example the vas deferens during a vasectomy operation. Vasectomy operations, of course, are well-known and serve the purposes of allowing an effective method of birth control by males and of limiting population growth.
Vasectomy operations are typically purely surgical procedures involving incision, transection of each of the two vasa deferens, tying or otherwise blocking each of the four lumina or severed ends of the vasa, misaligning the two severed ends of each of the two severed vasa, and closing the incision. These conventional techniques have had less than the desired success due to such factors as the ends of the vasa not correctly sealing and thereby causing spermatic granuloma, or the reestablishment of the duct passages. The typical failure rates in vasectomies, for one cause or another, has been estimated at 2 to 6 percent. This failure rate is relatively high and developments which reduce the rate are certainly important.
Equally desirable as the vasectomy itself is the ability to render the vasectomy operation reversible, that is, to allow the rejoinder of the previously severed vas through another surgical operation to once again cause the male to be fertile. Reversibility may become more important as the key factor to a wider acceptance and thus a higher incidence of vasectomies. The reversibility of vasectomies performed by conventional surgical techniques is extremely low. Typical reversibility techniques would involve surgery, excision of the sealed ends of the vas, stretching and aligning the now open ends of the vas, and retaining the vas in alignment so that healing to rejoin the vasa may occur. Apparently, tying the severed ends during conventional vasectomy operations induces significant trauma in the severed ends of the vas and requires excision of large amounts of the sealed vas and considerable stretching to realign the vas, all of which deters the proper healing. Another possible contributing cause which may reduce the success rate in reversing the vasectomy may be sperm antibody production. It has been discovered that in most conventional vasectomy operations significant amounts of sperm antibodies are generally present subsequent to the operation. The relationship between the reversal failures and the sperm antibodies is not certainly determined, but the presence of the sperm antibodies is suspected a contributing cause to the failure. Conventional vasectomy techniques have shown a marked proclivity for sperm antibody production, and to eliminate undue sperm antibody production may be to significantly increase the success rate of operation to reverse vasectomies.
It has recently been determined that electrocauterization of the lumen of the transected vas provides significant advantages over the conventional techniques in vasectomy operations. Electrocauterization virtually eliminates failures. Electrocauterization is a much faster procedure allowing a more rapid reclosure of the incision without the prolonged and sometimes difficult procedure of tying or otherwise blocking the transected vas. Furthermore the electrocauterization technique has shown a marked decrease if not elimination of the production of sperm antibodies subsequent to the operation. It has been determined that original electrocauterization of the transected vas has caused a higher rate of subsequent successful operations to rejoin the previously severed vasa. The operation to reverse the vasectomy is performed in the conventional manner, but apparently the electrocauterization of the lumen of the transected vasa in the original operation is the primary factor in determining the greater success in the operation to reverse the vasectomy.
At the time of original efforts to apply electrocauterization techniques to vasectomies, existing electrocautery apparatus was inappropriate due to the high power output supplied and the availability of only a conventional needle electrode and diffuse electrode or patient plate with which to apply the electrical energy during the electrocautery process. Furthermore known electrocautery apparatus was not portable due to the power requirements which normally require the use of conventional AC sources. Thus to effectively evaluate electrocauterization techniques in vasectomies, special vas cautery apparatus for such use was developed. Such apparatus was described in "An Electrocautery Instrument for the Fulguration of the Vas Deferens during Vasectomy for Sterilization", Proc. 10th Annual Rocky Mountain Bio-Engineering Symposium, 1973, pages 5-10 and in "Vas Cautery: Battery Powered Instrument for Vasectomy", in Urology, May 1964, page 604-605. The present invention defines significant improvements over the individual components of the known vas cautery apparatus, and thus provides a significantly more useable, reliable, and success-producing apparatus.
One of the principle deficiencies in known vas cautery apparatus involves the electrode used to apply the electrical energy during the cauterization. This electrode, known as a needle electrode, is bipolar, meaning there are two active electrodes between which the electrical energy flows to cause the cauterization. The bipolar needle electrodes originally used for vas cauterization were designed for other uses such as deep brain encephalographic recording and had to be considerably modified. Later versions of these needle electrode involved the use of hypodermic needles in which a center conductor and epoxy dielectric insulation were inserted through the internal bore of the hypodermic needle and a tip was soldered to the end of the center conductor. This version was more successful than the encephalographic electrode but was subject to many problems, particularly those relating to durability, strength and ease of production. Insulation of the conductors leading to the two active electrodes posed a considerable problem in the prior art. Generally the insulation consisted of epoxy dielectric material and such material was prone to break down and crumble due to the high temperatures during the cauterization process or during sterilization in an autoclave. The epoxy lacked the strength to adequately support the center conductor and was awkward to apply since the components were typically dipped in the epoxy and certain electrodes were exposed by scraping the epoxy after hardening. The soldered tip of the center conductor was prone to come loose and possibly fall off, which of course could create obviously serious consequences during an operation. The electrical connector for supplying power to the bipolar needle electrode was weak, and after limited repeated use was considerably weakened since the electrode pencil must be detached and sterilized after each operation. The prior art has counseled that solutions to many of these problems may be obtained by increasing the thickness of the dielectric epoxy adhesive. However, this solution is unacceptable since the overall outside thickness of the bipolar needle electrode would be increased thereby provoking problems during the insertion and use of the bipolar needle electrode in the transected vas. It is also questionable whether increased epoxy would solve the problems relating to breakdown of the insulation.
The known vas cautery electronic circuits provide a generally square pulse wave output of a positive polarity having the desired voltage amplitude, power and duty cycle characteristics. This arrangement has proved reasonably satisfactory, but certain disadvantages, deficiencies and areas for improvement are nevertheless present. The single polarity pulse output wave requires higher than necessary amounts of power from the battery to deliver the requisite energy for electrocauterization, which of course tends to decrease battery life, reduce the expected number of operations which may be performed, and slightly prolong the operative procedure since more output pulses are required to deliver sufficient energy. Typical experiences in analogous arts have shown that the single polarity pulse output wave may have a significant tendency to cause the degradation of the active electrodes of the bipolar needle electrode. The single polarity current usually causes an electrolysis-like action in depositing ions on the active electrodes. The prior art electronic cautery circuits have also generally failed to deliver consistent and repeatable output pulse waves, especially from the battery power supplies, which made consistency in operative results hard to obtain.
Known vas cautery apparatus further include a pencil hand control to which the bipolar needle electrode is connected and through which the pulse wave output is supplied to the bipolar needle electrode. A problem resulting from this arrangement is that the prior art electrical connector interfacing the pencil hand control to the bipolar needle electrode requires undue force in mating and separation, thereby decreasing the durability and lifetime of the bipolar needle electrode. Furthermore the materials from which the prior art pencil hand controls were made were not susceptible to withstanding repeated sterilization processes and were subject to deterioration or destruction at high temperatures or in other sterilization environments.
In view of the worthwhile objectives of vas cautery apparatus, it is a general object of this invention to provide an improved apparatus which may secure wider and more successful acceptance of vasectomies and enhance the success rate of vasectomies through vas electrocauterization.
It is an object of this invention to provide a very reliable and consistently operating vas cautery apparatus which may be relatively easily manufactured to thereby increase the distribution, use and availability of such apparatus.
It is another object of this invention to provide significant improvements to the durability, strength and design arrangement of known bipolar needle electrodes used in vas cautery apparatus.
It is another object of this invention to provide a new bipolar needle electrode for vas cautery apparatus which is of reduced cost and easily manufactured in large quantities to encourage the use of bipolar needle electrodes in situations where subsequent sterilization is not possible, since disposal of used bipolar needle electrodes of reduced cost and ready availability will not be prohibitive.
It is a further object of this invention to provide an improved vas cautery electrical circuit which delivers a unique waveform output to thereby increase battery life, increase power output and prevent degradation of the active electrodes of the bipolar needle electrode used in conjunction with the circuitry.
It is a further object of this invention to provide an improved electronic circuit for vas cautery apparatus which provides uniformly consistent output wave characteristics to thereby invoke more successful cauterization results.
It is still a further object of this invention to provide an improved cautery pencil device for a vas cautery apparatus which may be readily sterilized without destruction and which promotes increased durability of the bipolar needle electrode.
To secure these and other objects, the present invention provides improvements in individual components and to the vas cautery apparatus itself, encompassing improvements to the bipolar needle electrode, the cautery pencil and the cautery electronic circuitry. The improved bipolar needle electrode comprises individually manufactured parts, including a unitary center conductor and tip, with the tip forming one active electrode, a tubular outside conductor forming another active electrode and being separated from the center conductor by an insulating tubing, and insulation tubing surrounding the outer conductor except the exposed active electrode. This assembly is attached rigidly to a conventional push-pull electrical connector and a handle or grip is provided to easily insert and remove the bipolar needle electrode from its mating push-pull connector. The improved pencil hand control is comprised of plastic materials capable of withstanding the environments of all ordinary sterilization techniques, and specifically, includes the mating portion of the electrical push-pull connector of the bipolar needle electrode thereby allowing ready detachment. The improved vas cautery electronic circuit includes a voltage regulator to supply a consistant voltage reference level even as the battery degrades through use, and the output waveform provided has an alternating potential characteristic during periods of the waveform which increases power output and battery life and prolongs the life of the bipolar needle electrode.
The invention, as to its organization and method of operation and practice, together with further objects and advantages, will best be understood by reference to the following brief description of the drawings and detailed description of the invention.